Enhanced dielectric and ferroelectric properties of PVDF-BiFeO3 composites in 0-3 connectivity

Some composites fabricated with PVDF (Poly-Vinyl-difluoride) and BFO (BiFeO3) in 0-3 connectivity have been fabricated by a solution-casting method. The existence of all three polymorphic phases (a-, band g-) of PVDF in the composites is confirmed by analysing x-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectra. The intensity of the XRD peaks of the crystalline phase of the BFO ceramics increases with the increase of BFO filler concentration in the composites. Studies of micrographs recorded by scanning electron microscopy (SEM) technique reveal that the filler-particles have homogeneously been dispersed in the polymer matrix. The dielectric properties of the composites are very much dependent on both volume fraction of the filler and frequency of the applied field. The percolation threshold of electric field is observed in the composite at 50 vol percentage of BFO filler. A large enhancement in the dielectric constant and ferroelectric polarization in the composites is observed as compared to those of pure PVDF. With increase in BFO content in the composites, the leakage current density improves. Some IR inactive vibrational mode frequencies is found to be disappeared in the range of 400-800 cm(-1) in FTIR spectra indicating a possible interaction between some molecules of PVDF and BFO. Incorporation of BFO filler in the polymer matrix has resulted in increase of optical band gap. (C) 2017 Elsevier B.V. All rights reserved.